We started more than 50 years ago. The designs for the first metro lines were conceived at the drawing board, in work clothes, with a drawing pen and a slide rule. There was a revolution in design technology due to the advent of computers in the 1990s. The chance to modify a finished design without using a rubber was probably the most visible change on the outside. However, there was also an important contribution hidden in the speeding up and refinement of structural calculations, of which a considerable amount are needed in this type of underground construction. And nowadays? We still print drawings, but they are created as a by-product of the design, which is processed as a three-dimensional model of the structure.